Coil device for image pickup tube

Abstract

The invention provides a coil device having horizontal and vertical deflection coils around an outer surface of an image pickup tube to generate magnetic fields for deflecting electron beams in the horizontal and vertical directions, respectively. A correction coil is disposed between the outer surface of the image pickup tube and the horizontal deflection coil so as to correspond to the position of the vertical deflection coil. The number of turns of the correction coil is smaller than that of the vertical deflection coil. A signal for correcting scanning distortion of the electron beam caused by the deflection magnetic fields is supplied to the correction coil. The time constant of the correction coil is smaller than the period of the horizontal deflection signal. The correction coil is made of a printed circuit wiring.

We claim: 
     
       1. An image pickup device for a television camera comprising: an image pickup tube having a target and means for scanning the target with an electron beam and producing an electric signal corresponding to an image formed on said target;   a vertical deflection coil, surrounding said tube, for generating a vertical deflection magnetic field causing said electron beam to scan the target in the vertical direction;   a horizontal deflection coil, arranged between the image pickup tube and said vertical deflection coil and surrounding said tube for generating a horizontal deflection magnetic field causing said electron beam to scan the target in the horizontal direction;   a correction coil arranged between the tube and the horizontal deflection coil and surrounding said image pickup tube for generating a correction magnetic field in the same direction as said vertical deflection magnetic field, said correction magnetic field being generated in part of said vertical deflection magnetic field; and   a circuit for generating a correction signal having a period shorter than that of a horizontal drive pulse, the correction signal being supplied to said correction coil.   
     
     
       2. An image device for a television camera comprising: an image pickup tube having a target and means for scanning the target with an electron beam and producing an electric signal corresponding to an image formed on said target;   a horizontal deflection coil, surrounding said image pickup tube, for generating a horizontal deflection magnetic field causing said electron beam to scan the target in the horizontal direction;   a vertical deflection coil, arranged between the tube and the horizontal deflection coil and surrounding the periphery of said image pickup tube, for generating a vertical deflection magnetic field causing said electron beam to scan the target in the vertical direction; and   a correction coil arranged between said tube and said vertical deflection coil and surrounding said tube for generating a correction magnetic field in the same direction as said horizontal deflection magnetic field, said correction magnetic field being generated in part of said horizontal deflection magnetic field; and   a circuit for generating a correction signal having a period shorter than that of a horizontal drive pulse, the correction signal being supplied to said correction coil.   
     
     
       3. An arrangement according to claim 1, wherein said correction signal generating circuit comprises: a circuit for integrating a horizontal drive pulse signal; a linear direction circuit for generating a correction signal having a period shorter than that of said integrated signal; and a circuit for inverting said correction signal. 
     
     
       4. An arrangement according to claim 2, wherein said correction signal generating circuit comprises: a circuit for integrating a horizontal drive pulse signal;   a linear direction circuit for generating a correction signal having a period shorter than that of said integrated signal; and   a circuit for inverting said correction signal.   
     
     
       5. An arrangement according to claim 1 or 2, wherein said correction coil comprises a conductive layer which is printed on a flexible substrate. 
     
     
       6. An arrangement according to claim 1 or 2, further comprising a circuit for generating a correction signal which is supplied to said correction coil.